// 页面导出为pdf格式
import html2Canvas from 'html2canvas';
import jsPDF from 'jspdf';

const htmlToPdf = {
    getPdf(title, loading) {
        // loading = true;
        console.log(loading);
        html2Canvas(document.querySelector('#pdfDom'), {
            allowTaint: false,
            taintTest: false,
            logging: false,
            useCORS: true,
            dpi: window.devicePixelRatio * 4, //将分辨率提高到特定的DPI 提高四倍
            scale: 4, //按比例增加分辨率
        }).then((canvas) => {
            var pdf = new jsPDF('l', 'mm', [115, 200]); //A4纸，纵向
            var ctx = canvas.getContext('2d'),
                a4w = 190,
                a4h = 200, //A4大小，210mm x 297mm，四边各保留10mm的边距，显示区域190x277
                imgHeight = Math.floor((a4h * canvas.width) / a4w), //按A4显示比例换算一页图像的像素高度
                renderedHeight = 0;

            while (renderedHeight < canvas.height) {
                var page = document.createElement('canvas');
                page.width = canvas.width;
                page.height = Math.min(imgHeight, canvas.height - renderedHeight); //可能内容不足一页

                //用getImageData剪裁指定区域，并画到前面创建的canvas对象中
                page
                    .getContext('2d')
                    .putImageData(
                        ctx.getImageData(
                            0,
                            renderedHeight,
                            canvas.width,
                            Math.min(imgHeight, canvas.height - renderedHeight),
                        ),
                        0,
                        0,
                    );
                pdf.addImage(
                    page.toDataURL('image/jpeg', 1.0),
                    'JPEG',
                    5,
                    5,
                    a4w,
                    Math.min(a4h, (a4w * page.height) / page.width),
                ); //添加图像到页面，保留10mm边距

                renderedHeight += imgHeight;
                if (renderedHeight < canvas.height) {
                    pdf.addPage(); //如果后面还有内容，添加一个空页
                }
                // delete page;
            }
            //保存文件
            pdf.save(title + '.pdf');
            // loading = false;
            console.log(loading);
        });
    },
};

export default htmlToPdf;

